تباع بالحبه 
Dimensions: 
 4 Inch Outer Diameter.
 2.75 Inch Inner Diameter. 
 0.2 Inch Thickness/Height.
Compatible with
Dometic 300, Dometic 310, Dometic 320
Follow these Simple Hassle-Free Instructions:
 Step 1: Turn off water supply.
 Step 2: Press down the pedal to hold the flush ball open.
 Step 3: Grap the underside of the old seal and pull to remove.
 Step 4: Clean the rim and bowl area where the old seal was.
 Step 5: Release the flush pedal and let it close.
Step 6: Clean the flush ball.
 Step 7: Leave the flush ball closed. Put the new seal in and press down around entire edge until it is in place.
 Step 8: Reopen the flush ball and spread a lubricant in the areas where the gasket will contact the flush ball. 
 Step 9: Turn on the water supply, add water to the bowl and ensure that there are no leaks.